KVM: correct null pid check in kvm_vcpu_yield_to()

Correct a simple mistake of checking the wrong variable
before a dereference, resulting in the dereference not being
properly protected by rcu_dereference().

Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 27fbe64bfa63cfb9da025975b59d96568caa2d53)
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index b64d44219f27b8945ddd49a917805dec329f6372..9cae94206f413c2264c37dbb52a9a67a1e34fb04 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1728,7 +1728,7 @@ bool kvm_vcpu_yield_to(struct kvm_vcpu *target)
        rcu_read_lock();
        pid = rcu_dereference(target->pid);
        if (pid)
-               task = get_pid_task(target->pid, PIDTYPE_PID);
+               task = get_pid_task(pid, PIDTYPE_PID);
        rcu_read_unlock();
        if (!task)
                return ret;